Wood fiber has been used in the manufacture of paper and packaging since the mid 1800's. Although wood fiber continues to offer valued performance characteristics, its poor environmental profile has led to the search for alternative fibers to at least partially replace the wood fiber. Various non-wood fibers have been suggested, including sugar cane, bagasse, wheat and rice straws, bamboo, cotton stalks, banana leaves, fig leaves, reed, amur grass, and kenaf.
One potential source of non-wood fiber for use in paper materials is citrus fruit. Selected varieties of citrus fruit, including the sweet orange and the grapefruit, are processed commercially to provide juice and sections. About 45 to 60 percent of their weight remains post-processing, in the form of peel, rag, and seeds. The by-product volume is significant; Florida's citrus processing plants alone produce 5 million tons of wet citrus by-product annually. Citrus fruit therefore presents a potential non-wood fiber that could be useful in the manufacture of paper or packaging.
However, previous attempts to use citrus fiber in the production of paper products have resulted in materials with unacceptable properties for packaging commercial products. For example, paper or packaging materials including citrus fiber have historically exhibited levels of liquid uptake which result in a loss of packaging integrity or package failure. Liquid uptake at the cut edge of the material is a property known as “edge wicking,” and is an unacceptable problem for food and beverage packaging due to moisture levels that generally accompany food and beverage goods. In addition, the undesirable properties associated with the use of non-wood fiber into paper products increases with the amount of non-wood fiber used as a substitute for wood fiber. As a result, paper products including citrus fiber have not been adopted for the packaging or storage of commercial liquid products.